JP2006313216A - Oscillator device and optical deflector using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with an accurate tuning operation in compensating an angular velocity of a scanning angle or a rotational angle in an oscillator device such as a resonance optical deflector. <P>SOLUTION: The oscillator device constituting a resonance optical deflector or the like is equipped with: supporting means 102, 103 which rotatably support an oscillator 101 in a range with a neutral position as the center around a nearly prescribed rotary shaft; restoring torque generating means 102, 104, 105, 108 which generate a restoring torque T in a direction returning the oscillator 101 to the neutral position; and driving means 106, 107, 108 which drive the oscillator 101 in a manner rotating and oscillating it with the neutral position as the center around the rotary shaft. The device has a nonlinear characteristic in which dT/dθ is smaller when the restoring torque T is monotonically decreases relative to displacement angle of arc θ from the neutral position of the oscillator 101, and in addition when the absolute value of the displacement angle becomes larger. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an oscillating body device that rotates an oscillating body about a rotation axis (vibration), an optical deflector using the oscillating body device, and more particularly to a technical field of a resonant optical deflector using mechanical resonance. And an image forming apparatus such as a scanning display, a laser beam printer, or a digital copying machine using the resonance type optical deflector.

Conventionally, various types of resonant optical deflectors in which mirrors are driven to resonate have been proposed. The resonance type optical deflector has the following characteristics as compared with an optical scanning optical system using a rotating polygon mirror such as a polygon mirror. That is, it is possible to greatly reduce the size, power consumption is low, there is no inconvenience in theory, and the resonant optical deflector made of Si single crystal manufactured by the semiconductor process is theoretically metal fatigue. There is a characteristic that it has no durability and excellent durability (see Patent Document 1).

On the other hand, a resonance type optical deflector in which the mirror rotates and rotates around the rotation axis has a characteristic that the angular velocity is not constant because the scanning angle (rotation angle) of the mirror changes in a sinusoidal manner in principle. In order to correct this characteristic, the following method has been proposed (see Patent Document 2).

In Patent Document 2, a resonance type deflector having a vibration mode having a fundamental frequency and a frequency three times that of the fundamental frequency is used, and the fundamental wave and the third harmonic wave are overlapped, so that a substantially triangular wave drive (wide forward and backward paths in rotational vibration) is achieved. In each region, the angular velocity is substantially constant). In this method, two vibration modes are accurately tuned when an optical deflector is manufactured, and angular velocity correction is performed by using these vibration modes during driving.
JP 57-8520 A U.S. Pat. No. 4,859,846

However, the method disclosed in Patent Document 2 requires an accurate tuning operation.

In view of the above problems, an oscillating body device constituting the resonant optical deflector of the present invention includes a supporting means for rotatably supporting the oscillating body around a predetermined rotation axis in a range centered on a neutral position. A restoring torque generating means for generating a restoring torque T in a direction to return the moving body to the neutral position; and a driving means for driving the oscillating body to rotate around the rotation axis about the neutral position to vibrate. T has a non-linear characteristic that decreases monotonously with respect to the displacement angle θ from the neutral position of the oscillating body, and dT / dθ decreases as the absolute value of the displacement angle θ increases. In other words, this non-linear characteristic means that as the angle from the neutral position (absolute value) of the oscillating body increases, the torque for returning the oscillating body toward the neutral position increases, and the angle from the neutral position (absolute value). This is a characteristic that the rate of change in which the torque to be returned to the neutral position increases as the value increases. However, the restoring torque T and its rate of change need not always change, and there may be a region that does not substantially change, and it is only necessary to change as described above as a whole. The design may be performed according to the degree of correction to the desired triangular wave drive.

In view of the above problems, an image forming apparatus of the present invention includes a light source, a light source modulating unit that modulates the light source, an oscillator device configured as an optical deflector, a light source modulating unit, and an optical deflector. It has the control means to control, It is characterized by the above-mentioned.

According to the present invention, an accurate tuning operation is not required to correct the scanning angle or the rotational angular velocity of an oscillator device such as a resonant optical deflector.

The embodiment of the present invention will be described while explaining the principle of the oscillator device of the present invention with reference to the drawings. The principle of a resonance type optical deflector having a deflecting mirror that twists and vibrates around a torsion bar will be described. However, this principle is generally used for driving an oscillating body device that oscillates an oscillating body about a rotation axis. Is true.

FIG. 8 is a schematic view of one embodiment for illustrating the principle of an oscillator device such as a resonant optical deflector of the present invention. Reference numeral 901 denotes a deflection mirror, and 902 denotes a torsion bar. The deflection mirror 901 is elastically supported by two torsion bars 902, and the other ends of the two torsion bars 902 are fixed. The resonance type optical deflector causes resonance by applying an external excitation force to the deflection mirror 901 (excitation force at the time of resonance, but driving force at driving other than resonance). Drive. Here, as shown in FIG. 9, the displacement angle from the neutral position of the deflection mirror 901 (the position where the torsion bar is not twisted and the deflection mirror 901 rotates and vibrates in the range centered on this position). (Rotation angle) is represented by θ, and the restoring torque acting around the axis is represented by T, and the clockwise direction in the figure is positive (or vice versa). The oscillator device such as the resonance type optical deflector of the present invention is characterized in that the restoring torque T acting on the deflection mirror 901 has characteristics as shown in FIGS. 10 (A) and 10 (B). That is, the restoring torque T decreases monotonously with respect to the displacement angle θ (there may be a so-called dead zone in which T becomes substantially constant in the middle), and dT / dθ decreases as the absolute value of the displacement angle θ increases ( The degree of non-linear characteristics may be set according to circumstances. Considering this characteristic as a spring, it corresponds to a non-linear spring in which the spring constant increases as the absolute value of the displacement angle θ from the neutral position increases.

Here, if the moment of inertia of the deflection mirror 901 is I and the attenuation is ignored, the equation of motion of the oscillator device such as the resonance type optical deflector is
I · d ² θ / dt ² = T (θ) (Formula 1)
It becomes. FIGS. 11A and 11B are plots of θ (t) and dθ (t) / dt that satisfy the equation of motion of Equation 1 against time t, respectively. From FIG. 11, in the vicinity of the neutral position where the absolute value of the displacement angle θ is small, the restoring torque T is relatively small, so that the angular velocity fluctuation (change in dθ / dt) is small, and the region where the absolute value of the displacement angle θ is large. Then, since the restoring torque T becomes relatively large, it can be seen that the angular velocity fluctuation (change in dθ / dt) increases. Therefore, it can be understood that the rotational angular velocity of the oscillator device can be corrected as desired by giving the restoring torque T non-linear characteristics as described above.

As described above, in the present invention, as described above, when the displacement angle is θ and the restoration torque is T, the restoration torque T decreases monotonously with respect to the displacement angle θ, and the absolute value of the displacement angle θ increases. dT / dθ has a nonlinear characteristic that decreases (its absolute value increases). By utilizing this non-linear characteristic, an oscillator device such as a resonant optical deflector having a small angular velocity fluctuation (ie, approaching a triangular wave drive) near neutral is realized.

In particular, the resonance type oscillator device such as the resonance type optical deflector of the present invention tends to increase the resonance frequency when the amplitude increases due to the non-linear characteristic of the restoring torque T. By utilizing this characteristic, a resonant oscillator device such as a resonant optical deflector capable of controlling the drive frequency by controlling the amplitude can be realized.

Next, the principle of the restoring torque generating means of the present invention for generating the restoring torque having the above characteristics will be described with reference to an embodiment. FIG. 12 is a schematic view of an embodiment of an oscillating device such as a resonant optical deflector according to the present invention as viewed from the direction of the rotation axis (the same principle applies to a cantilever-type oscillating device). 905 is a deflection mirror, 906 is a torsion bar, 907 is a movable permanent magnet, and 908 is a static magnetic field H.

As shown in FIG. 12, the displacement angle from the neutral position (horizontal direction in the figure) of the deflection mirror 905 and the movable permanent magnet 907 is θ. For simplicity, assuming that the static magnetic field H of 908 is uniform (actually, for example, it may be weak in the periphery), the torque T _m acting on the movable permanent magnet 907 is:
T _m = HMsin θ (Formula 2)
(See FIG. 13A). Here, M is a magnetic moment of the movable permanent magnet 907 (this kind of torque can be generated by other than the magnetic moment).

On the other hand, the restoring force T _s of the torsion bar 906 is
T _s = −kθ (Formula 3)
(See FIG. 13B). Here, k is a torsion spring constant of the torsion bar 906 (this kind of torque can be generated by other than torsional force).

Since the restoring torque T acting on the deflection mirror 905 is the sum of T _m and T _s ,
T (θ) = T _m + T _s = −kθ + HMsin θ (Formula 4)
(See FIG. 13C). From this, it can be seen that the restoring torque T is a function of the displacement angle θ, and has a non-linear characteristic that decreases monotonously with respect to the displacement angle θ and decreases dT / dθ as the absolute value of the displacement angle θ increases. . That is, it can be read that this restoring torque T has a property equivalent to a spring such as a torsion bar or an elastic spring whose spring constant increases as the displacement angle increases. Further, as can be seen from Equation 4, by changing the static magnetic field H, the nonlinear characteristic of the restoring torque T can be controlled. Of course, the characteristic curve can be controlled by changing the spring constant k. These designs may be performed according to the desired rotational vibration period, frequency, amplitude, degree of approach to triangular wave driving, and the like.

As already mentioned, the method for generating the restoring torque as shown in FIG. 10 is not limited to the above example, and various methods are possible. For example, the combination of the torque by the elastic spring and the torque by the magnetic moment as described above in the cantilever-type oscillating body, or the torque and oscillating by the urging means such as a leaf spring that hits the oscillating body near the end of the rotational vibration range and gives this a restoring torque. A combination of torques by a supporting means (for example, a torsion bar having a very weak torsion spring constant) that supports the moving body so as to be able to rotate and vibrate almost freely is possible. In the case of the latter combination, the restoring force in FIG. 13A (in this case, the magnetic moment is not used) is almost zero in the region of the displacement angle near the neutral position, and the displacement angle near the end of the rotational vibration range. (Θ rises in the minus direction when the plus is on the side, and rises in the plus direction when the θ is on the minus side, and the shape of FIG. 13C becomes more steep on the plus and minus sides. It will be like a changed shape). On the other hand, the restoring force by the supporting means in FIG. 13B is almost zero, and the shape is substantially along the horizontal axis of the displacement angle.

As described above, in the present invention, by using a torque acting on a movable permanent magnet and a restoring torque such as a torsion bar, an oscillator device such as a resonance type optical deflector having a small angular velocity fluctuation near neutral is realized. can do. For driving means or vibration means for driving the oscillating body so as to oscillate around the rotation axis, voltage is alternately applied to the means described in the following embodiments, the driving electrode attached to the oscillating body and the driving electrode on the support substrate side. There are means for applying an electrostatic attractive force to the rocking body by applying and rotating it around the rotation axis.

Hereinafter, specific examples will be described with reference to the drawings.

[Example 1]
FIG. 1A is a top view of the resonance type optical deflector according to the first embodiment, and FIG. 1B is a cross-sectional view taken along line AA ′. In FIG. 1, 101 is a deflecting mirror that is a rocking body, 102 is a torsion bar that supports the deflecting mirror (here, two are used on both sides of the deflecting mirror 101, but only one may be used on one side), and 103 is supported. (Together with the torsion bar 102, which constitutes support means for rotatably supporting the deflection mirror 101), 104 is a magnetic pole made of a magnetic material, 105 is a fixed permanent magnet, 106 is a drive coil, and 107 is a coil made of a magnetic material A magnetic core, 108 is a movable permanent magnet attached to a deflection mirror, 110 is a base, and 111 is a spacer. The elements 101 to 103 are integrally formed by etching a single crystal silicon substrate, and the surface of the deflection mirror 101 is coated with a light reflecting film. The base 110 and the spacer 111 are also integrally formed from a metal material. The movable permanent magnet 108 and the fixed permanent magnet 105 are magnetized so that the north and south poles are in the directions shown in FIG. That is, the movable permanent magnet 108 is magnetized in a direction substantially perpendicular to the torsion axis that defines the rotation axis of the torsion bar 102 and substantially parallel to the surface of the oscillator, and the magnetic field generated by the fixed permanent magnet 105 is movable. The direction is substantially parallel to and opposite to the magnetization direction of the permanent magnet 108.

First, the restoring force (torque) generating means (including the torsion bar 102, the magnetic pole 104 made of a magnetic material, the fixed permanent magnet 105, and the movable permanent magnet 108) according to the present embodiment will be described. FIG. 2 shows magnetic field lines 191 of the magnetic field created by the magnetic pole 104 and the fixed permanent magnet 105 in the space. 2 that a substantially horizontal magnetic field is generated in the vicinity of the movable permanent magnet 108 from left to right in FIG. However, the magnetic field in this space is not uniform and becomes weaker toward the periphery. Due to the magnetic field created in this space, torque having the same characteristics as in FIG. 13A acts on the movable permanent magnet 108. Further, since the elastic restoring torque of the torsion bar 102 exhibits the characteristics as shown in FIG. 13B, the restoring torque as shown in FIG. Therefore, it can be seen that the resonance type optical deflector of this embodiment performs a rotational vibration motion with a small variation in angular velocity in a region centered on the neutral position as shown in FIG.

Next, a description will be given of the vibration or drive means (referred to as vibration means at the time of resonance, but referred to as drive means at driving other than resonance) according to the present embodiment. FIG. 3A is a schematic view when a current is passed through the coil 106 so that the tip of the coil magnetic core 107 has an S pole. As shown in the figure, the magnetic field lines come out from the bottom of the coil magnetic core 107 and enter the tip thereof, and torque acts on the movable permanent magnet 108 counterclockwise in the figure (in this embodiment, The movable permanent magnet 108 is a component of the restoring torque generating means and a component of the driving means). On the other hand, as shown in FIG. 3B, when a current is passed through the coil 106 in such a direction that the tip of the coil magnetic core 107 is N-pole, a torque acts on the movable permanent magnet 108 clockwise in the figure. Become. That is, it can be seen that by passing an alternating current through the coil 106, an alternating magnetic field can be applied to the movable permanent magnet 108 substantially perpendicular to the magnetization direction, and the deflection mirror 101 with the movable permanent magnet 108 can be driven. By making the drive frequency at this time substantially equal to the resonance frequency of the deflection mirror 101, the resonance type optical deflector of this embodiment can be driven to resonance.

As described above, according to the present embodiment, it is possible to realize a resonance type optical deflector having a small angular velocity fluctuation near neutrality. Further, by controlling the amplitude of the resonance vibration (this is performed, for example, by controlling the intensity of the current flowing through the coil 106), a resonance type optical deflector capable of controlling the drive frequency can be realized. In the resonance type optical deflector of this embodiment, it is not necessary to match a plurality of resonance frequencies, so that an accurate tuning operation is unnecessary. In addition, since it is not necessary to excite a plurality of vibration modes at the same time, power consumption is reduced. In addition, since the structure is simple, downsizing is easy and the cost is reduced.

[Example 2]
4A and 4B respectively show a top view and a front view of the resonance type optical deflector according to the second embodiment. In FIG. 4, 201 is a deflection mirror, 202 is a torsion bar that supports the deflection mirror, 203 is a support, 204 is a magnetic pole made of a magnetic material, 206A and 206B are static magnetic field generating coils, and 210 is a base. Reference numeral 220 denotes a vibration actuator, which includes a deformable member 221 and stacked piezoelectric elements 222A and 222B. The elements 201 to 203 are integrally formed by etching a single crystal silicon substrate, and the surface of the deflection mirror 201 is coated with a light reflecting film. Similar to the first embodiment, a movable permanent magnet is disposed on the back side of the deflection mirror 201 (not shown in FIG. 4).

First, the restoring force generating means (including the torsion bar 202, the magnetic pole 204 made of a magnetic material, the static magnetic field generating coils 206A and 206B, and a movable permanent magnet (not shown)) according to the present embodiment will be described. When a current is passed through the static magnetic field generating coils 206A and 206B so that the right side of the magnetic pole 204 is the south pole and the left side is the north pole, the deflection mirror 201 to which the movable permanent magnet (not shown) is attached is the same as in the first embodiment. A similar restoring torque acts. Therefore, it can be seen that the resonance type optical deflector of the present embodiment performs the rotational vibration motion with little fluctuation in the angular velocity in the region centered on the neutral position as in the first embodiment.

Next, the vibration means of the present embodiment will be described. FIG. 5 is a diagram for explaining the operation of the vibration actuator 220 of this embodiment. When a voltage is applied in the direction in which the stacked piezoelectric element 222A contracts and 222B extends, the deformable member 221 deforms as shown in FIG. If the expansion and contraction of the stacked piezoelectric elements 222A and 222B is reversed, the rotation direction of the support portion 203 around the torsion bar 202 is reversed. From these facts, it is understood that the deflection mirror 201 can be driven by applying an alternating voltage to the two stacked piezoelectric elements 222A and 222B. By making the drive frequency at this time substantially equal to the resonance frequency of the deflection mirror 201, the resonance type optical deflector of the present embodiment can be driven to resonance.

In the resonance type optical deflector of the present embodiment, resonance driving with small angular velocity fluctuations near neutrality can be performed by passing a current through the static magnetic field generating coils 206A and 206B. Further, if no current is passed through the static magnetic field generating coils 206A and 206B, it can be used as a normal resonance type optical deflector, and the degree of angular velocity fluctuation and the resonance frequency can be controlled by the amount of current passed. The drive frequency can also be controlled by controlling the amplitude (for example, by controlling the intensity of the voltage applied to the multilayer piezoelectric elements 222A and 222B). In the resonance type optical deflector of this embodiment, it is not necessary to match a plurality of resonance frequencies, so that an accurate tuning operation is unnecessary. The other points are the same as in the first embodiment.

[Example 3]
In the first and second embodiments, the oscillating body is rotationally oscillated around the torsion axis of the torsion bar. However, the oscillating body is a cantilever-type oscillating body made of an elastic body, and this oscillating body is a base near the fixed end. It can also be rotated and vibrated by the bending of the part. FIG. 6 is a cross-sectional view showing the resonance type optical deflector according to the third embodiment having such a configuration. In FIG. 6 showing the present embodiment, reference numeral 501 denotes a deflecting mirror which is a cantilever vibrator, 506 denotes a drive coil, 508 denotes a movable permanent magnet attached to the deflecting mirror, 510 denotes a base, and 511 denotes one end of the deflecting mirror. It is a spacer that is fixed and supported. In this configuration, the restoring torque generating means includes a movable permanent magnet 508 attached so as to move integrally with the deflection mirror 501, a static magnetic field generating means for generating a static magnetic field 191 for the movable permanent magnet 508, and a supporting means. It consists of a deflectable root portion 501a in the vicinity of the fixed end of the deflection mirror 501 constituting a part. The movable permanent magnet 508 is magnetized in a direction substantially perpendicular to the extending direction of the base portion 501a that defines the rotation axis (direction perpendicular to the paper surface of FIG. 6) and substantially parallel to the surface of the deflection mirror 501. The magnetic field 191 generated by the static magnetic field generating means is substantially parallel to the magnetization direction of the movable permanent magnet 508 and opposite in direction.

The rotation vibration indicated by the arrow in FIG. 6 of the cantilever type deflection mirror 501 of the present embodiment is also performed in the same manner as in the first embodiment by the drive coil 506 and the movable permanent magnet 508 which are vibration or driving means. As described in the first embodiment, the rotational vibration motion with little fluctuation of the angular velocity is achieved in the region centered on the neutral position by the action of the magnetic lines of force 191. Instead of the drive coil 506, the stacked piezoelectric element described in the second embodiment can be used at the spacer 511 that fixes and supports one end of the deflection mirror 501, and the drive system of the second embodiment can be used.

The same effect as that of the above-described embodiment can be obtained in the third embodiment that uses the cantilever-type vibrating body that utilizes the bending of the root portion 501a near the fixed end.

[Example 4]
FIG. 7 is a schematic diagram for explaining an optical scanning display of Example 4 using the resonant optical deflector of the present invention. The laser beam 310 emitted from the laser light source 303 is scanned in the horizontal direction by the first optical deflector 301 of the present invention, and then scanned in the vertical direction by the second optical deflector 302 to form an image on the screen 320. Form. The driving of the optical deflectors 301 and 302 and the modulation oscillation of the laser light source 303 are controlled in synchronization by the control device 304. That is, the control device 304 includes light source modulation means for modulating the light source 303 based on the image signal, and control means for controlling the light source modulation means and the optical deflectors 301 and 302.

In the optical scanning display of this embodiment using the first optical deflector 301 of the present invention capable of substantially triangular wave driving as the horizontal scanning means, scanning is performed at the scanning central portion and the peripheral portion with respect to the horizontal direction by using an fθ lens or the like. The difference in speed can be reduced and good image formation can be realized. Further, since the optical deflector according to the present invention is used, it is possible to provide an image forming apparatus that is smaller, consumes less power, and is low in cost. Note that the oscillator device of the present invention can be used in any device that requires its substantially triangular wave drive.

(A) is a top view of the resonant optical deflector of the first embodiment, and (B) is a cross-sectional view of the resonant optical deflector of the first embodiment. It is a figure explaining the static magnetic field generation | occurrence | production means of the resonance type optical deflector of Example 1. FIG. FIG. 3 is a cross-sectional view for explaining excitation or driving means of the resonance type optical deflector according to the first embodiment. (A) is a top view of the resonant optical deflector of the second embodiment, and (B) is a front view of the resonant optical deflector of the second embodiment. It is a figure explaining the excitation thru | or drive means of the resonance type optical deflector of Example 2. FIG. 6 is a cross-sectional view of a resonance type optical deflector according to Embodiment 3. FIG. It is a figure explaining the optical scanning type display of Example 4. FIG. It is a figure explaining the structure of one Embodiment of this invention. It is a figure explaining the symbol used for the principle explanation of the present invention. It is a graph explaining the restoring torque T of the present invention. It is a graph explaining displacement angle (theta) of this invention. It is a figure explaining the generation | occurrence | production principle of the restoring torque of this invention (represented by one Embodiment). It is a graph explaining the generation | occurrence | production principle of the restoring torque of this invention.

Explanation of symbols

101, 201, 501, 901, 905 Oscillator (deflection mirror)
102, 202, 902, 906 Torsion bar (support means, restoring torque generating means)
103, 203 Support part (support means)
104, 204 Magnetic pole (restoration torque generating means)
105 Fixed permanent magnet (restoration torque generating means)
106, 506 Driving coil (driving means)
107 Coil core (drive means)
108, 208, 508, 907 Movable permanent magnet (driving means, restoring torque generating means)
191, 908 Static magnetic field H (restoring torque generating means)
206A, 206B Static magnetic field generating coil (restoring torque generating means)
220 Excitation actuator (drive means)
221 Deformation member (drive means)
222A, 222B Multilayer piezoelectric element (drive means)
301 First optical deflector (oscillator device of the present invention)
303 Light source (laser light source)
304 control device (control means, light source modulation means)
506a oscillating body root (supporting means, restoring torque generating means)

Claims (10)

Support means for rotatably supporting the rocking body around a predetermined rotation axis in a range centered on the neutral position, restoring torque generating means for generating restoring torque T in a direction to return the rocking body to the neutral position, and rocking body Driving means for rotating the shaft around the neutral position to vibrate, and the restoring torque T monotonously decreases with respect to the displacement angle θ from the neutral position of the oscillator and is displaced. An oscillator device having non-linear characteristics in which dT / dθ decreases as the absolute value of the angle θ increases. The restoring torque generating means is a movable permanent magnet attached so as to move integrally with the oscillating body, a static magnetic field generating means for generating a static magnetic field with respect to the movable permanent magnet, and the support attached to the oscillating body. The movable permanent magnet is magnetized in a direction substantially perpendicular to the torsion axis defining the rotation axis of the torsion bar and substantially parallel to the surface of the oscillating body. The oscillator device according to claim 1, wherein the magnetic field generated by is substantially parallel to and opposite to the magnetization direction of the movable permanent magnet. The oscillating body is an elastic oscillating body that vibrates by rotating in a cantilever manner, and the restoring torque generating means is attached to a movable permanent magnet that is attached so as to move integrally with the oscillating body. It comprises a static magnetic field generating means for generating a static magnetic field and a bendable root near the fixed end of the oscillating body constituting the support means, and the movable permanent magnet is substantially in the extending direction of the root defining the rotating shaft. The magnetic field generated by the static magnetic field generating means is substantially parallel to and opposite to the magnetization direction of the movable permanent magnet, and is magnetized in a direction that is orthogonal and substantially parallel to the surface of the oscillator. 2. The oscillator device according to 1. The oscillator device according to claim 2 or 3, wherein the static magnetic field generating means includes a permanent magnet. The oscillator device according to claim 2 or 3, wherein the static magnetic field generating means includes a coil. 6. The oscillator device according to claim 2, wherein the driving unit includes an alternating magnetic field generating unit that applies an alternating magnetic field to the movable permanent magnet substantially perpendicular to the magnetization direction. 6. The oscillator device according to claim 2, wherein the driving means includes a piezoelectric element. The rocking device according to any one of claims 1 to 7, wherein the driving unit is a vibrating unit that vibrates the rocking body around the rotation axis, and can constitute a resonance-type rocking body device. Moving body device. 9. The oscillator device according to claim 1, wherein the oscillator is a deflection mirror and constitutes an optical deflector. An image forming apparatus comprising: a light source; a light source modulating unit that modulates the light source; an optical deflector according to claim 9; and a control unit that controls the light source modulating unit and the optical deflector.

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